Screw-thread-rolling machine.



W. L. KERLIN. SCREW THREAD ROLLING MACHINE.

APPLICATION FILED OCT-15,1913;

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W. L. KERLIN. SCREW THREAD ROLLING MACHINE.

APPHCATION FILED OCT. I5. 1913.

Patented Nov. 7, 1916.

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7 WITNESSES W. L. KERUN.

SCREW THREAD ROLLING MACHINE.

APPLICATION FILED 00?.15. {9Y3- 4335, Patented Nov. '7, 1916,

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W. L. KERLIM SCREW THREAD ROLLING MACHlNE.

APPLICATION HLED OCT. 15, I913.

Patented Nov. 2, 1916 5 SHEETS-SHEET 5.

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WILLIAM L. KERLIN, OF NEW YORK, N. Y., ASSIGNOR TO EDWARD R. WELLES, OF NEW YORK, N. Y.

' Specification of Letters Patent.

Patented Nov. *7, 1916.

Application filed October 15, 1913. Serial No. 795,181.

To all whom it may concern Be it known that 1, WILLIAM L. KiinLiN, a citizen of the United States, and a resident of New York. in the county of New York and State of New York, have invented certain new and 'useful Improvements in Screw-Thread-Rolling Machines, of which the following is a specification.

This invention relates to improvements in screw bolt threading machines of that type in which a hot bolt or shank is fed in between a plurality of circumferentially disposed threading dies and by such dies impressed with the desired screw thread.

The main object of the invention is to reduce the size of machines of this type and to render them less complicated than heretofore, thus reducing the cost of manufacture and the amount of floor space hereto lar disposition of the shafts complex ad-' justing mechanism at each end thereof is necessary to take care of variations in the size of threads it may be desired to roll, as

well as variations in the size of bolts upon which it is desired to roll the threads. Also the machines are so long owing to the necessity of providing sufficient space at one end for the driving connections that it is impractical for one operator to do the necessary adjusting on the machine.

According to this invention the die roller shafts are parallel and for this reason may be comparatively very short. Also they are mounted'in a single casting whereby but a single adjustment of the drive shaft takes care of any diameter of bolt it is desired to thread. Also by a simple circumferential adjustment the roller dies may be adjusted to track perfectly with each other. Also simple mechanism is provided for bodily moving but one of the roller dies to discharge the finished bolt.

The invention consists in the improved screw bolt threading machine and in the novel parts, combinations of parts and details of construction hereinafter more particularly described and then specified in the claims.

In the accompanying drawings, Figure 1 is a side elevation of a machine illustrating a practical embodiment of the present invention, parts being broken away for clearne'ss. Fig. 2' is an enlarged horizontal section of a part of the machine taken on the line 2 2 Figs. 1 and 3. Fig. 3 is a front elevation. on an enlarged scale, of that part of the machine shown in Fig. 2. Fig. 4 is a longitudinal section of the forward part of the machine taken on the line l, a Fig. 3 and looking in the direction of the arrows. Fig. 5 is a cross-section on the line 5, 5 Fig. 4 and illustrating part of the driving transmission. Fig. (3 is a detached view of another part of the transmission, view taken on line 6, 6 Fig. l. Fig. 7 is a detached plan view of part of the bolt releasing Inechanism. Fig. 8 is an enlarged fragmentary side view of the bolt releasing actuating mechanism. Fig. 9 is a cross-section through the tracking adjustment for the roller dies. Figs. 10, 11 and 12 are views of a device for pointing or tapering the end of the bolt.

In the drawings, 1 indicates the base of the machine on which the various operating devices and mechanisms are supported.

2 indicates the main shaft of the machine supported in suitable bearings formed in standards 3, 4 rising from and secured to the base 1. The shaft 2 is provided with a loose pulley 5 and a fixed pulley 6 through which latter pulley said shaft is driven from any suitable source of power by a driving belt (not shown) in an obvious manner. The driving belt may be shifted from the loose to the fast pulley and vice versa by a belt shifter 7 (Fig. 1) having a handle 8 brought forward to the front of the ma chine for convenience in operation. It will beunderstood that the main shaft 2 may be driven in any desired manner, the specified manner of driving being no part of this invention. The forward end of the shaft 2 is provided with a gear wheel 9 fixed thereon.

10, 11 and 12 indicate counter-shafts disposed parallel to each other and to the main shaft and each arranged in a corner of a triangle formed by the axes of said shafts. Said counter-shafts are suitably mounted to rotate in bearings formed in a casting or standard 13 rising from the base 1.

Counter-shafts 10, 11 and 12 are geared to and driven by the main shaft 2 through the gear wheel 9 and gear wheels 14, 15, 16 on the shafts 10, 11 and 12 respectively. The gear wheel 14 is preferably fast on the shaft while the gears 15 and 16 are preferably secured on their shafts by a friction device to be presently described. It will be understood that any two or all the gears 14, 15 and 16 may be frictionally held on their respective shafts.

The gear wheels 15 and 16 are secured to i the shafts 11 and 12 respectively as follows,

both securing means being the same; a description of one will apply to both: 17 indicates a sleeve keyed to the shaft 11 at the rear end and provided with a beveled shoulder 18. The gear wheel 15 fits loosely about the periphery of the sleeve 17 and is provided with an internal bevel corresponding with the bevel shoulder 18 of the sleeve. The end of the sleeve projects beyond the side of the gear wheel and at such end a cap or nut 19 is screwed thereto, the end of said cap bearing against the side of the gear wheel 15. 20 indicates a washer superimposed on the cap or nut 19 and pressed against said cap by a bolt 21 tapped into the end of the shaft 11 to lock the cap or nut 19 in place. Upon tightening up the nut 19 the gear 15 is securely fastened to the shaft 11 by being gripped between the shoulder 18 and nut 19 so that a rotation of the gear will cause the shaft to rotate. Upon loosening bolt 21 and nut 19 the shaft 11 can be rotated in either direction, while the gear 15 remains stationary, the object of this feature being to track the threads on the roller dies as will be presently described. 22, 23 and 24 indicate roller die shafts disposed parallel to each other in the form of a triangle in end view and each provided on its forward end with a removable roller die 25 upon which is formed the thread desired to be rolled on the bolt or screw. Each shaft is provided with a pinion 26 fixed on its opposite end and each pinion meshes respectively with a gear wheel 27 lreyed on each of the shafts 10, 11 and 12. Thus rotation from the main shaft 2 is transmitted to the roller die shafts 22, 23 and 24 through gear 9. gears 14, 15, 16, counter-shafts 10, 11 and 12, gear wheels 27 and pinions 26 on the ends of the shafts 22,

23 and 24.

Preferably the upper roller die shaft 22 is rotatively mounted in a fixed position in an elongated bearing '28 formed in the standard 13. The roller die shaft 24 is rotatively mounted in an elongated bearing 29 formed in the end of one arm of a lever 30 fulcrumed on the counter-shaft 12, the other arm of said lever being held fixedly between two adjustable clamps 31 and 32 mounted on the side of the machine. By means of the clamps 31 and 32 the roller die shaft 24 may be bodily adjusted to any desired position for different sized bolts upon which the threads are to be rolled or for different size dies employed. It will be observed that the roller die shaft being swung bodily about the counter-shaft 12 to adjust it, no further adjustments are necessary for the transmission as the driving pinion 26 of said shaft merely swings about the gear wheel 27, maintaining the teeth in mesh.

The roller shaft 23 is rotatively mounted in an elongated bearing'33 formed in one arm of a lever 34 fulcrumed on the countershaft 11. The other arm of the lever 34 is spread out fan-shaped and is provided along its edge with a toothed segment 35 secured to the lever by a bolt and slot connection 36. The lever 34 is loosely swiveled on the counter-shaft 11 and is provided with a slot 37 in which a rearwardly extending lug or flange 35 on the segment is secured. The toothed segment 35 and the lever 34 are normally held in a fixed position by a vertically disposed rack bar 38. by which the roller shaft 23 is swung about the counter-shaft 11 to discharge the bolt, as will be presently described, but the lever 34 is adjustable relative to the segment to adjustthe position of the roller shaft 23 to accord with any adjustment given the roller shaft'24. This adjustment is effected by a set screw 39 secured to the upper side of the lever. and engaging one end of the segment 35 and a set screw 40 secured to the lower side of the lever 34 and engaging the lower end of the toothed segment By loosening the bolt and slot connection 36 it will thus be seen that the lever 34 carrying the roller shaft 23 may be adjusted in one direction or the other by the set screws 39 and 40, said set screws serving to securely hold the lever in adjusted position in relation to the segment, although it will be understood that the set screws may be dispensed with. and the bolt and slot device relied upon to hold the lever 34 and segment 35- in relative adjusted posi-' tion and that other means may be employed to adjust the lever 34 and shaft 23 to correspond with the adjustment of the shaft 24 without departing from the spirit of this invention.

41 indicates the bolt holder of any suitable or well known design which is provided with a cavity to receive the head of the bolt or screw to be threaded, the shank of which projects forwardly toward the roller dies 25. The bolt holder is carried on the end of a shaft 42 supported in a bearing formed in the upper part of an adjustable support 43. The support 43 is slidably mounted in the end of a bracket 44 secured to the base 1 and is held in adjusted position by a bolt and nut 45 working in a slot 46, the support being further sustained by a set screw 47. The shaft42 and bolt holder 41 are adjusted to such position, according to the size bolt to be threaded, that the axis of the bolt held 'in the holder 41 will be in line with the axis of the roller dies 25, that is in line with the center of the triangle formed by the aXes of the three roller dies. The shaft 42 is reciprocated toward and away from the roller dies 25 by an operating handle 48 working 011 said shaft through the medium of a lever 49 and link 50.

Referring more particularly to Figs. 1, 7 and 8, the end of the shaft 42 remote from the holder 41 is provided with a screw thread and a nut 51 thereon adapted to be adj ustedin position along the threaded portion of the shaft 42. 52 indicates an upright lever fulcrume'd on the bracket 44 and provided at its upper end with a yoke 53 freely spanning the shaft 42 and in position to be struck by the nut 51 when the shaft 42 has traveled forward the requisite distance. The

.lower arm of the lever 52 is connected jao side of the rack bar 38 and is slidably supported in a lug secured to the base of the machine. The free end of the lever 57 engages a groove or slot in the latch 59, the latch being normally held pressed against 4 the rack bar by a tension spring 62 pulling on the lever 57, said spring also tending to maintain the actuating lever 52 in normal position. The lever 52 is also provided with a handle 63 whereby thelatch 59 may be tripped by hand at any time desired without waiting for the nuts 51 to actuate the lever 52.

Referring more particularly to Figs. 1 and 3, the rack bar 38 is provided with suitable teeth along one side and is adapted to reciprocate vertically in suitable guides to maintain it in vertical position. As has been previously described, the teeth at the upper end of the bar mesh with the teeth on the segment 35, the lower end ofthe bar terminating in a slotted toe 64depending from and in line with the bar. Av shaft 65 mounted transversely across the base of the machine and'in bearings formed in the sides thereof is provided with a weighted lever 66 keyed thereto and extending rearwardly from the shaft. A lever 67 also keyed to the shaft 65 engages the notch in the toe 64 of the rack bar 38. The weight 66 is held in suspended position as shown by the latch 59 and when the latch has been withdrawn, due to actuation of the lever, the weight 66 is released and rotates the shaft 65. This rotation of the shaft 65 causes the lever 67 to raise the rack bar 38 and turn the segment about its fulcrum on the shaft 11. This movement carries the roller shaft 23 away from its co-acting roller shafts 22 and 24 and allows the bolt which may be between the roller dies to drop down into a trough 68 through which it passes and is discharged at the side of the machine. 69 indicates a shaft disposed longitudinally of the machine and mounted in suitable bearings in standards secured to the base 1. Said shaft is driven from the main shaft 2 through a train of gears 70 at the rear end of the machine. Shaft 69 is provided with a gear wheel 71 (Figs. 3 and 4) loosely mounted thereon and so disposed that the teeth mesh with the teeth on the rack bar 38. The gear wheel 71 is provided with a toothed clutch member 73 and the shaft 69 is provided with a co operating clutch member 72 keyed thereon but capable of longitudinal movement on the shaft as is usual to couple and uncouple the clutch members, the clutch members being normally disengaged. 74 indicates a yoke for the movable clutch member 72 which is provided with laterally projecting pins 75 which work in a groove formed in the clutch member. The yoke 74 is pivotally mounted in a bracket 76 and is provided with a laterally projecting lever arm 77. Vhen the rack bar 38 travels upwardly a sufficient distance, a pin 78 carried thereby engages the under side of the lever 77 and forces the clutch member 72 into engagement with clutch member 73 by swinging the yoke 74 about its pivot in an obvious man The rotation of the shaft 69 then drives the rack bar 38 downward by means of the gear wheel7l until the upper surface of the ley'er 77 is struck by a lug 79 carried by the rack bar, which action disengages the clutch members, at which time the notch in the bar is engaged by the latch 59. The clutch operating pin 78 is preferably backed up by a spring 80 so that the clutch members will be gradually forced together and not by a sudden or abrupt force. 81 indicates a treadle keyed to the shaft 65 by which the rack bar 38 can be returned by the foot to its original position at any time irrespective of the clutch. The treadle acts to rotate the shaft 65 and pull down the bar by means of the lever 67 in an obvious manner.

Referring moreparticularly to Figs. 10, 11 and 12, 82 indicates a collar adji'istably secured on the periphery of the roller die shaft bearing 33 and provided with a cut or groove 83. 84 indicates a collar adjustably secured to the periphery of the roller die shaft bearing 29 in line with the collar 82 and provided with a cut or groove 85 corresponding with and adjoining the cut 83 of the collar 82. 86 indicates a fin secured to and projecting laterally from the collar 84 at the cut or groove thereof, said fin bein provided with a surface similar to the surfaces of the grooves 83 and 85 and projecting toward the collar 82 as shown in Fig. 11. The grooves 83, 85 and fin 86 are in the path of the end of the bolt fed between the roller dies 25 and said bolt being hot and forced into the space in the grooves said grooves taper or round theends of the bolts as the case may be, depending upon the nature of the surface given the bolt engaging grooves in the collars.

As is well understood in the art, the threads on the roller dies 25 must track with each other, that is the development of them must be a straight line. To secure this in the most simple manner the friction coupling of the gear wheels 15 and 16 is provided. By loosening the cap or nut 19 on the shaft 11 or 12 or both, the respective shaft may be rotated more or less until the threads on the roller dies track with each other without moving the gear wheel 16 or 15. This adjustment may be made by the application of a suitable tool to the gear wheel 27 or otherwise after which the gear wheels 16 and 15 may be fastened on their respective shafts by tightening the nuts 19. As has been previously stated, this adjustment may be provided for any or all the roller shafts 22, 23 and 24.

In the operation of the machine, after the proper dies 25 have been secured to'their respective shafts and their position adjusted according to the size of the bolt to be operated upon by regulating the positions of the shafts 23 and 24 by means of the adjusting screws 31 and 32 for the shaft 24 and 39 and 40 for the shaft 23 and after the threads on the roller dies 25 have been regulated to track by loosening the cap or nut 19, the bolt while still hot is placed in the holder 41, the holder being in the position shown in Fig. 1 or farther back, if desired, according to the length of the bolt. The feed lever 48 is then pressed forward until the end of the shank of the bolt enters the space between the roller dies 25 which are rotating from power applied to the pulley 6 through the transmission previously described. The bolt is pulled inwardly by the rolling of the threads thereon and continues to travel iflwardly until the desired length of thread has been rolled thereon, the nuts 51 being adjusted to strike the yoke 53 when this condition takes place. A further travel of the bolt carrier shaft 42 causes the lever 52 to be rocked about its pivot and the latch 59 is withdrawn from the notch 61 in the rack bar 38 through the links and levers previously described. As soon as the bar is released from the latch the weight 66 ment actuates the segment 35. The turning of the segment 35 moves the roller die shaft 23 and its attached die away from the dies on the shafts 24 and 25 and the bolt drops down into the chute 68 and thence to the floor or a hopper at the side of the machine. The bar 38 travels upward and therefore the shaft 23 away from the cooperating shafts until the clutch operating pin 7 8 in its up ward travel engages the underside of the lever arm 77. lVhen the pin 78 engages the lever arm the clutch members 7 2 and 7 3 are engaged and the rotation of the shaft 69 brings the rack bar downward until the lug or projection 79 strikes the upper surface of the lever arm 77 at which time the catch or latch 59 has again engaged the notch 61 in the rack bar. The lug 79 disconnects the clutch members 72 and 73 and the bar and roller die shaft 23 is held in its initial position ready for another bolt. During the return travel of the rack banthe bolt holder 41 is returned to its initial position by the feed lever 48, the spring 62 automatically resetting the lever 52. l/Vhen it is desired to roll a different thread, dies hav- 17. forces it upward and this upward move-' ing the proper threads thereon are substituted on the ends of the shafts 22, 23 and 24 and the friction devices for securing the gear wheels 15 and 16 to the counter-shafts 11 and 12 respectively are loosened to permit tracking adjustment of the dies, after which the gears are securely fastened to drive the roller die shafts. When it is desired to roll threads on bolts of a larger or smaller diameter, the die shafts 23 and 24 are adjusted as previously described, the shaft 24 being adjusted by screws 31 and 32 and the shaft 23 by screws 39 and 40 carried by the segment 35. If it is desired to provide a rounded or taper end on the bolt or screw, the tapering collars 82 and 84 are adjusted to proper position to be engaged by the end of the bolt or screw at about the end of the thread rolling operation.

It will be understood that the invention is not limited to the specificdetails of construction as herein shown and described for carrying the same into effect but that various modification and equivalents within the scope of the appended claims may be resorted to. 7

What I claim as my invention is V 1. In a screw thread rolling machine, the combination of a plurality of parallel shafts, roller dies on the ends of said shafts and a lever one arm of which forms a support forv one of said shafts. i

2. 111 a screw thread rolling machine, the

combination of a plurality of parallel roller die shafts and an adjustable lever forming a support for one of said shafts.

3. In a screw thread rolling machine, the combination of a plurality of parallel roller die shafts having driving pinions at one end, levers having arms adapted to bodily carry two of said shafts and means acting 011 said levers for adjusting the position of said shafts.

4. In a screw thread rolling machine, the combination of a plurality of parallel roller die shafts, driving pinions at one end of said shafts, a lever in one arm of which one of said shafts is rotatively mounted and means acting on the other arm of said lever to adjust the position of said shaft.

5. In a screw thread rolling machine, the combination of a plurality of parallel roller die shafts having driving pinions thereon,

means for bodily adjusting one of said shafts and means for bodily moving another of said shafts to automatically discharge the bolt from between the roller dies.

6. In a screw thread rolling machine, the combination of a plurality of parallel roller die shafts having driving pinions thereon, means for bodily adjusting one of said shaft-s means for bodily moving another of said shafts to automatically discharge the bolt from between the roller dies and means for adjusting said latter shaft.

7. In a screw thread rolling machine, the combination 'of a main shaft, counter-shafts driven by said main shaft, levers fulcrumed on said counter-shafts, parallel roller die shafts carried by said levers and driving connections between said counter-shafts and said die shafts.

8. In a screw thread rolling machine, the combination of a main shaft, counter-shafts driven by said main shaft, levers fulcrumed on said counter-shafts, parallel roller die shafts carried by said levers, gear wheels secured to said counter-shafts and pinions secured to said die shafts in mesh with said gear wheels.

9. In a screw thread rolling machine, the combination of a main shaft, counter-shafts driven thereby, parallel roller die shafts driven by said counter-shafts, levers fulcrumed on said counter-shafts for supporting said die shafts and means for adjusting the position of said levers about their fulcrum as and for the purpose described.

10. In a screw thread rolling machine, the combination of a main shaft, roller die shafts driven thereby, a die on the end of each die shaft and a friction coupling adapted to disconnect the driving couple between said shafts to permit tracking said dies.

11. In a screw thread rolling machine, the combination of a main shaft, a countershaft driven thereby, a roller die shaft driven by said counter-shaft and a friction coupling adapted to disconnect the driving connection between the main shaft and said counter-shaft to permit rotative adjustment of said die shaft.

12. In a screw thread rolling machine, the combination of a main shaft, a countershaft geared to said main shaft, a roller die shaft geared to said counter-shaft and a friction coupling for disconnecting the main shaft gearing from the counter-shaft to permit rotative adjustment of said die shaft.

13. In a screw thread rolling machine, the combination of a main shaft, a countershaft, a roller die shaft geared to said counter-shaft, a gear wheel on said main shaft, a gear wheel loose on said countershaft in mesh with said main shaft gear wheel and means for frictionally securing said gear wheel to said counter-shaft as and for the purpose described.

14. In a screw thread rolling machine, the combination of a main shaft, a roller die shaft driven thereby, a lever in which said die shaft is rotatively mounted, bolt feeding mechanism and a rack bar automatically brought into action at a predetermined point of travel of said feeding mechanism and adapted to operate said lever substantially as and for the purpose described.

15. In a screw thread rolling machine, the

combination of a bolt feeding mechanism,

a bolt releasing device comprising a lever and a toothed rack engaging said lever, a latch for holding said releasing device inoperative, a weight adapted to operate said releasing device and means actuated by said feeding mechanism to automatically release said weight and operate said releasing device.

16. In a screw thread rolling machine, the combination of a main shaft, bolt feeding mechanism, a bolt releasing device comprising a lever and a toothed rack engaging said lever, a latch for holding said device inoperative, means independent of said shaft for actuating said releasing device when said latch is inoperative and means actuated by said shaft for resetting said releasing device.

17. In a screw thread rolling machine, the combination of a main shaft, bolt feeding mechanism, a bolt releasing device comprising a lever and a toothed rack engaging said lever, a latch for holding said device inoperative, a weight adapted to actuate said device upon releasing said latch and means connected with and operated by said shaft for re-setting said releasing device.

18. In a. screw thread rolling machine, the combination of a main shaft, a bolt feeding mechanism, a bolt releasing device comprising a toothed segment, a rack for actuating said segment, means adapted to actuate said rack at a predetermined point in the travel of said feeding mechanism and a gear wheel operated by said main shaft and adapted to return said rack to its original position.

19. In a screw thread rolling machine, the combination of a main shaft, bolt feeding mechanism, a bolt releasing device adapted to be brought into operation at a predetermined point in the travel of said feeding mechanism, means independent of said shaft and adapted to actuate said releasing device and mechanism comprising a clutch automatically brought into operation and actuated by said shaft and adapted to re-set said releasing device.

20. In a screw thread rolling machine, the combination of a main driving shaft, bolt feeding mechanism, a bolt releasing device comprising an actuating rack bar, means for moving said rack bar in one direction to actuate said device, an auxiliary shaft driven by said main shaft and connected with said rack bar and a clutch automatically ope 'ated to cause said auxiliary shaft to re-set said rack bar.

21. In a screw thread rolling machine, the combination of a main driving shaft, bolt feeding mechanism, a bolt releasing device comprising a reciprocating rack bar, a latch operating on said rack bar to maintain said device inoperative and to be released at a predetermined point in the travel of said feeding mechanism, means adapted to move said rack bar in one direction when released, an auxiliary shaft connected to said main shaft and to said rack bar, a clutch for said auxiliary shaft normally disengaged and means for coupling said clutch after said releasing device has been in operation to reset said device.

22. In a screw thread rolling machine, the combination of a. main driving shaft, bolt feeding mechanism, a bolt releasing device comprising a reciprocating rack bar, a latch operating on said rack bar to maintain said device inoperative and to be released at a predetermined point in the travel of said feeding mechanism, means adapted to move said rack bar in one-direction when released, an auxiliary shaft connected to said main shaft and to said rack bar, a clutch for said auxiliary shaft normally disengaged, means for coupling said clutch after said releasing device has been in operation to re-set said device and means for uncoupling said clutch after said device has been re-set.

23. In a screw thread rollingmachine, the combination of a main driving shaft, bolt feeding mechanism, a bolt releasing device comprising a reciprocating rack bar, alatch operating on said rack bar to maintain said device inoperative and to be released at a predetermined point in the travel of said feedingmechanism, means adapted to move said rack bar in one direction when released, an auxiliary shaft connected to said main shaft and to said rack bar, a clutch for said auxiliary shaft normally disengaged, means carried by said rack bar for automatically coupling said clutch to re-set said releasing device and means carried by said rack bar adapted to automatically uncouple said clutch after said device has been reset.

Q-i. In a screw thread rolling machine, the combination of a stationary roller die shaft, two adjustable roller die shafts and a vertically adjustable bolt feeding device.

In a screw thread rolling machine, the combination of bolt feeding mechanism, a

. plurality of roller dies adapted to apply the thread to the bolt and a pointing or tapering device adapted to be engaged by the end of the bolt prior to the end of travel of said feeding mechanism.

26. In a screw thread rolling machine, the combination of bolt feeding mechanism, a plurality of roller dies adapted to apply the thread to the bolt and collars adjustably mounted back of said dies and provided with surfaces adapted to taper the end of the bolt fed between said dies substantially as and for the purpose described.

Signed at New York in the county of New York and State of New York this 9th day of October, A. D. 1913.

\VILLIAM L. KER-LIN.

Witnesses F. B. TowNsnND, IRENE LEFKOWITZ.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

